Handheld devices for rounding corners for stationery and card-laminating purposes are known. One example is the commercially available “3 mm Radius Corner Rounder Punch Cutter—Heavy Duty Clipper” sold by Oregon Laminations Company. Cutters such as this use punch-like handles terminating in jaws, with a backer plate on the lower jaw having a blade-receiving shear recess or aperture, and with an arcuate shearing blade on the upper jaw. These devices are used for cutting aesthetic rounded corners in paper, cardboard, and laminated paper items.
U.S. Pat. No. 4,106,195 to Berg discloses handheld punch-type cutters for making aesthetic V-shaped cuts on decorative molding.
A common problem encountered in the flat roofing industry is the need to cut uniformly rounded corners in sheet-type roofing materials such as EPDM, PVC, or TPO thermoplastic roofing materials that comes in roll form. Roof sections with improperly rounded corners usually fail inspection and need to be re-done. Hand cutting with scissors or knives is also tiresome and time consuming.